Dual Monitors on M1 Mac mini

I have very similar symptoms with my Mac mini M1 running 2 x BENQ PD2700u 4k monitors via HDMI from the mini and DisplayPort from a CalDigit TS3+ dock.

I can sometimes resolve this without a hard reboot by selecting a different system settings display resolution for either monitor. this seems to reset the displays.

I have very similar symptoms with my Mac mini M1 running 2 x BENQ PD2700u 4k monitors via HDMI from the mini and DisplayPort from a CalDigit TS3+ dock.

I can sometimes resolve this without a hard reboot by selecting a different system settings display resolution for either monitor. this seems to reset the displays.

So the problem is not just caused by HDMI connections. Any ideas on fixing would be appreciated.

Hi braintoniq,

how did you go with the USB3 to DP port test?

I continue to have the same issue as described above, and I fix it each time by resetting the resolution on either monitor - doesn't matter if you scale it down or up - it sort of slaps the M1 in the face and it stops flickering, you then have to reset the monitor arrangement as they swap from right to left, and it then works perfectly until next time it sleeps.

There is no need to reboot or to pull out cables or anything like that but would be good to find a proper resolution to the issue rather than this workaround.

J

I had a similar situation when I first got the M1 Mac Mini. I am using a 34" Alienware and a 27" Alienware with an HDMI and a DP to Thunderbolt cable. It works for the most part - the only issue (which is very minor) is that I have to always select the input on the 34". But once I do so, I have both monitors working fine.

Hey Jeffory, I have just bought a PD2700U to check it out with the Mac mini M1. I am considering buying another one as a dual monitor. Would love to hear how did your test go with the USB3->DP mini? Or did you come up with another solution. I could always buy a Benq thunderbolt display, but at the end of the day I just need a solid 4k like the PD2700U. I don't need the added expense. Any update on your efforts would be much appreciated here,

P.

Hi Wally,

I have been running two PDU2700Us using the Mini M1 and a CalDigit TS3+ thunderbolt dock connected via the USBC/TB port. This worked without any problems once I sorted out the connections and installed the late-December version of BigSur (there was some flickering on wakeup on the shipped OS version).

I was not able to get both monitors to run at high resolutions from just the M1 using various adaptors (in fact that was a while ago so maybe it just didn't work at all) Either way I was buying a TB dock anyway so decided to use it to enable a dual highres 4k setup.

One BENQ is connected the the the MacMini's HDMI port and is running at 60HZ at 3840x2106. The second is running from the DisplayPort(1.3) of the TS3+ also at 60Hz 3840x2106.

Switching between different resolutions is really fast when you need to and the BENQs provide a rock solid fantastic value for money 4K experience. These are really great monitors and I would only go more upmarket if I needed to do professional graphics/film work - and I think these would be fine for that anyway.

Meanwhile the M1 just stays cool and quiet on tasks that had my MBP fans maxing out (prior to getting the M1 I was running the BENQs directly from the MBP).

Hope that helps.

That is fantastic, I think that makes up my mind, I have OWC Thunderbay 4 (thunderbolt) connected to the Mac Mini M1, it has a DisplayPort connector and it can run the monitor.

I will get another PD2700u monitor, connect it and see if it works with the HDMI of the M1 and the Displayport on the OWC Thunderbay 4.

If not, I will get the CalDigit TS3.

That was a great help, thanks for taking the time, it is very much appreciated.

thanks!

While most here are talking about dual PD2700u monitors, any thoughts you can provide on how to get the following to work one at a time only -

1) Mac Mini M1

2) MacBook Pro 2015 (presently using the PD2700u provided DisplayPort cable)

3) Nvidia Shield TV via HDMI

My goal is simply to use them one at a time and want to use DisplayPort for the Mini at 4k@60. My concern is making sure I get 4k@60 and not 4k@30 which I heard could happen. Any thoughts on what is the best way to handle all of these devices and use the "KVM" control on the monitor to switch?

(I have to get a hub at some point so is not a problem if that is the way to an end but obviously prefer a direct connect.)

Thanks in advance

UPDATE: Two Monitors working on a Mac Mini M1 16gb

Thanks Jeffory - I have a successful set up. I bought the mac mini M1 with 2 - BenQ PD2700U and a OWC Thunderbay 4 (thunderbolt) which also has a DisplayPort 1.2 port at the back.

I have a HDMI connected directly to one of the monitors. The thunder bay is connected to the Mac Mini M1 via the included thunderbolt cable and the second monitor is connected to the DisplayPort 1.2 port in the back of the Thunderbay. I am using no adapters anywhere and all cables are relatively short. Less than 1.5metres.

It works perfectly, wakes from sleep without issue. Have not had to restart I have the set up 4 days already and I work all day on the machine. On another note I do fid some blue tooth glitches, hanging etc. I am running the latest Mac updates as of 20th Feb 2021.

Wally, I do appreciate the focus of this particular thread. I was hoping that as people are doing different test combinations, that perhaps one problem solver would have checked to see if DisplayPort on the BenQ would work sans connection to HDMI whether direct cable or via a dock. If so, it wouldn't take but a moment to respond. Please know I had no desire to redirect the thread but get a snippet of test info.

Oh I misunderstood your question. I tested it just now for you. I unplugged the hdmi from the back of the Mac mini m1 and started up the mini. My benq pd2700u works on its own via the mini display port on the back of the thunderbay 4 Using the DisplayPort cable. The thunderbay is attached to the m1 mini via thunderbolt.

Wally, thank you very much for taking the time. In the near future I will be going a similar route with a hub (although a combo hub and drives is something to think about) and will do a break out with the DisplayPort. I have an old MBP 2015 that works brilliantly with mini DP out to DP on the BenQ. The HDMI works great with my Nvidia TV Shield. Last stop is the Mac Mini M1 to be attached to the Mini DisplayPort that is left unpopulated on the monitor. Again, thanks for your effort and sharing.

The M1 Mac mini can run two displays only if one is connected to the HDMI port.